The most common type of controller for music synthesizers is the piano type keyboard, a long row of single pole single throw switches with one side in common, actuated by piano-key type lever mechanisms, with related voltage divider, control, envelope generator and voltage controlled oscillator circuits.
There are also ribbon type controllers, which permit continuously varying control signals to be derived from linear motion of a hand across a voltage divider.
Controllers have also been designed to imitate other musical instruments, including harmonicas, guitars, trumpets and flutes.
The prior art electronic music controller, e.g., a depressed key, produces a control voltage and a trigger pulse. The control voltage determines frequency and the trigger pulse a pre-selected envelope. Knobs, switches and patch cords are separate controls for musical parameters. A single operator can only operate two keyboards at a time, and thus is limited to two control voltages and two "triggers."
This limitation also does not permit the "bending" of notes or the playing of chords.
The prior art video game controller, referred to as a "joy stick" includes the "discrete controller," which contains four switches at the four main compass points. When tilted to the left, it instructs movement of the video character to the left, but it can only instruct in one of eight directions--the four compass points and diagonals, and cannot instruct how far or how fast the character should move.
"Proportional" joy sticks can be varied, like the volume control of a radio, permitting direction, speed and distance in any direction.
The "trackball" controller, operated by rolling the palm over a billiard ball protruding from a box, allows movement in all directions, at speeds determined by how fast the ball is spun. The spinning ball turns two shafts, controlling vertical and horizontal movement on the screen. Attached to the shafts are wheels with holes through which light shines on a photocell activating the video character.
Conventional joy sticks have only one firing button.